Why can I only use Input.GetAxis from Void Start or Void Update

Unity Engine
1

I cannot use it Input.GetAxis defined ias a variable with my horizontalInput ; and public float verticalInput ;variables

I get this error message

UnityException: GetAxis is not allowed to be called from a MonoBehaviour constructor (or instance field initializer), call it in Awake or Start instead. Called from MonoBehaviour ‘Move’ on game object ‘player’.
See “Script Serialization” page in the Unity Manual for further details.
Move…ctor () (at Assets/scripts/Move.cs:11)

I have tried in my variables before void start below and commented it our in void update for verticalInput

It works when it is activated in Void Update

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Move : MonoBehaviour
{

    public int speed = 1;
    public float horizontalInput ;
    //public float verticalInput ;
    public float verticalInput  = Input.GetAxis("Vertical");



    // Start is called before the first frame update
    void Start()
    {
        //transform.position = new Vector3(0, 4, 0);
    }

    // Update is called once per frame
    void Update()
    {

         horizontalInput = Input.GetAxis("Horizontal");
         //verticalInput = Input.GetAxis("Vertical");

        transform.Translate(new Vector3(horizontalInput, verticalInput, 0) * speed * Time.deltaTime);


        // transform.Translate(Vector3.left * speed *Time.deltaTime);
    }
}
2

So line 10 VS 26 of the code

3

All the “assignment code” (e.g. in line 11) in a class happens only once, when a class is created, and is never run again. Unity’s protecting you, because even if it did allow that code to run, it wouldn’t do anything. You need to retrieve the input values each frame for it to be valid… so do it in Update.

Yes, and that’s the correct place to do that. Why are you trying to do the other thing?

3 Likes
4

I was used to defining all of my variables before void start but what you are saying makes sense.

Thanks

5

Even if Unity let you do this, it would be the same as just saying
public float verticalInput = 0;

Input.GetAxis just tells you what that axis is doing right now; it doesn’t create some kind of permanent connection to the axis.

2 Likes
6

Debug.Log(“LA CASA Y EL GALLO”);
Debug.Log(“Comienza la aventura. Tienes 3 vidas. Suerte…”);
Debug.Log(“Estás frente a una puerta ¿Tocas el timbre (1) o Golpeas la puerta (2)?”);
if (Input.GetKeyDown(“1”)) //SITUACIÓN1
{
Debug.Log(“Se abre una compuerta secreta debajo y caes al sótano”);
Debug.Log(“Pierdes una vida. Te quedan 2 vidas”);
Debug.Log(“En el sótano hay un gallo y una puerta.”);
Debug.Log(“¿Lo levantas (1) o Lo llamas (2)?”);
if (Input.GetKeyDown(“1”)) //SITUACIÓN2
{
Debug.Log(“Te da un picotazo.”);
Debug.Log(“Pierdes una vida. Te queda 1 vida…”);
Debug.Log(“El gallo cacarea, alguien arriba lo escucha y baja por las escaleras…”);
Debug.Log(“¿Te escondes (1) o Te quedas quieto (2)?”);
if (Input.GetKeyDown(“1”))//SITUACIÓN3
{
Debug.Log(“Nadie te encuentra jamás.”);
Debug.Log(“Te da demasiada hambre.”);
Debug.Log(“Pierdes tu última vida.”);
Debug.Log(“PERDISTE…”);
}
if (Input.GetKeyDown(“2”))//SITUACIÓN3
{
Debug.Log(“Llega un viejo con una escopeta y te dispara.”);
Debug.Log(“xd”);
Debug.Log(“Pierdes tu última vida.”);
Debug.Log(“PERDISTE…”);
}

When i run it, and i press like 1, the 1 continues til the end of the game…
Help please

7
  • please do not necro old, unrelated posts
  • open your own topic, it is free
  • please use code tags, ** read this ** how you can do that
  • you have multiple if (Input.GetKeyDown("1")), one after the other, this means all of these run at the same time once one becomes true
  • please share your whole script and we can figure out what you’re doing wrong
  • please describe what is your goal, so we can help how you can achieve it
1 Like